On the Horton–Rogers–Lapwood convective instability with vertical vibration: Onset of convection

Bardan, Gérald; Mojtabi, Abdelkader

doi:10.1063/1.1313551

Cited by 77 publications

(23 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This layer deepens in the course of the summer and reaches its maximum in fall, when its influence on the debris is the strongest. The profile of the circulation inside the debris in the course of the year is the reason for the relatively high differences inside Ice Gulch between the air temperature at the vegetation boundary and in the debris, especially in summer (Bardan and Mojtabi, 2000;Cheng et al, 2007;Nield and Bejan, 1992).…”

Section: Analysis and Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Talus-and-gorge ice caves in the northeastern United States past to present—A microclimatological study

Holmgren¹,

Pflitsch²,

Rancourt³

et al. 2017

JCKS

View full text Add to dashboard Cite

The focus of this article is both a region and a type of cave not typically associated with ice caves. Nevertheless, both the region and the type play an important role in American ice-cave research. Talus-and-gorge ice caves in the northeastern United States can be used as climate indicators for a whole region; and therefore, they are the target of this young field of research. Ice caves, in general, are sensitive climatopes that can serve as excellent indicators for short and long term changes in the climate of a region, principally because of shifts between phases of increasing ice growth and melting during a year and over time. This research started with an investigation of known talus-and-gorge ice caves, followed by environmental monitoring of selected caves with perennial ice that were equipped with temperature sensors recorded over four years. This is one of the world's longest high-resolution climatologic monitoring record of such caves. In addition, the height of the ice was surveyed annually at a time when ice would most likely be at its minimum, the start of November. This allowed for investigation of the annual changes and the influence of the temperature over the previous year. Some predictions for the future of the ice caves and the whole region could be deduced from the data. At the moment, there is no sign of either a renewed increase in the number of talus-and-gorge ice caves or an increase in ice accumulation within the existing ones.D. Holmgren, A. Pflitsch, K. Rancourt, and J. Ringeis. Talus-and-gorge ice caves in the northeastern United States past to present-A microclimatological study.

show abstract

Section: Analysis and Discussionmentioning

confidence: 99%

“…Edwin Swift Balch was one of the first to investigate the phenomenon of ice caves for purely scientific purposes. He visited numerous ice caves and reported all his observations in various articles and a book (Balch, 1897;Balch, 1899;Balch, 1900).…”

Section: Introductionmentioning

confidence: 99%

Talus-and-gorge ice caves in the northeastern United States past to present—A microclimatological study

Holmgren¹,

Pflitsch²,

Rancourt³

et al. 2017

JCKS

View full text Add to dashboard Cite

show abstract

“…Malashetty and Padmavathi [14] asymptotically analyzed the linear stability of a horizontal fluid-saturated porous layer heated from below for the case of small-amplitude gravity modulation. Bardan and Mojtabi [15] studied numerically and analytically convection in a rectangular saturated porous cavity heated from below and subjected to highfrequency vibration.…”

Section: Effect Of Vertical Modulation On Filtration Convection 489mentioning

confidence: 99%

Effect of Vertical Modulation on the Onset of Filtration Convection

Strong

2007

J. math. fluid mech.

View full text Add to dashboard Cite

The present paper examines the effect of vertical harmonic vibration on the onset of convection in an infinite horizontal layer of fluid saturating a porous medium. A constant temperature distribution is assigned on the rigid boundaries, so that there exists a vertical temperature gradient. The mathematical model is described by equations of filtration convection in the Darcy-Oberbeck-Boussinesq approximation. The linear stability analysis for the quasiequilibrium solution is performed using Floquet theory. Employment of the method of continued fractions allows derivation of the dispersion equation for the Floquet exponent σ in an explicit form. The neutral curves of the Rayleigh number Ra versus horizontal wave number α for the synchronous and subharmonic resonant modes are constructed for different values of frequency Ω and amplitude A of vibration. Asymptotic formulas for these curves are derived for large values of Ω using the method of averaging, and, for small values of Ω, using the WKB method. It is shown that, at some finite frequencies of vibration, there exist regions of parametric instability. Investigations carried out in the paper demonstrate that, depending on the governing parameters of the problem, vertical vibration can significantly affect the stability of the system by increasing or decreasing its susceptibility to convection. (2000). 76E15, 76S05, 35Q35. Mathematics Subject Classification

show abstract

“…Mojtabi [11], and the Grashof number, ( Gr = gβ T ΔTh 3 / ν 2 ), without vibration at the paraffin wax.…”

Section: With Vibration Presented By Bardan Andmentioning

confidence: 99%

Experimental Study of Vibration Effects on Heat Transfer during Solidification of Paraffin in a Spherical Shell

Vadasz

Meyer

Govender

et al. 2015

Experimental Heat Transfer

View full text Add to dashboard Cite

Two effects that have been observed when metals and metal alloys are vibrated during solidification are a decrease in dendritic spacing, which directly affects density, and faster cooling rates and associated solidification times. Because these two effects happen simultaneously during solidification it is challenging to determine the one effect independently from the other. Most previous studies were on metals and metal alloys. In these studies, the one effect, i.e. the decrease in dendritic spacing, might influence the other, i.e. the faster cooling rates, and vice versa. The direct link between vibration and heat transfer has not yet been studied independently. The purpose of this study was to experimentally investigate the effect of vibration only on heat transfer and thus solidification rate. Experiments were conducted on paraffin wax, because it had a clearly defined macroscopic crystal structure consisting of mostly large straight-chain hydrocarbons. The advantage of the large straight-chain hydrocarbons was that the dendritic spacing was not affected by the cooling rate.Experiments were done with paraffin wax inside hollow plastic spheres of 40 mm 2 diameter with 1 mm wall thickness. The paraffin wax was initially in a liquid state at a uniform temperature of 60°C and then submerged into a thermal bath at a uniform constant temperature of 15°C, which was approximately 20°C below the mean solidification temperature of the wax. Experiments were conducted in approximately 300 samples, with and without vibration at frequencies varying from 10 -300 Hz.The first set of experiments were conducted to determine the solidification times. In the second set of experiments, the mass of wax solidified was determined at discrete time steps, with and without vibration. The results showed that paraffin wax had vibration independent of solid density contrary to other materials, eg. metals and metal alloys. Enhancement of heat transfer resulted in quicker solidification times and possible control over the heat transfer rate. The increase in heat transfer leading to faster solidifcation times was observed to first occur, as frequency increased and then to decrease.

show abstract

On the Horton–Rogers–Lapwood convective instability with vertical vibration: Onset of convection

Cited by 77 publications

References 26 publications

Talus-and-gorge ice caves in the northeastern United States past to present—A microclimatological study

Talus-and-gorge ice caves in the northeastern United States past to present—A microclimatological study

Effect of Vertical Modulation on the Onset of Filtration Convection

Experimental Study of Vibration Effects on Heat Transfer during Solidification of Paraffin in a Spherical Shell

Contact Info

Product

Resources

About